Hello,
You can choose the thicknesses of the board and the weight of the copper .
Outer Layer Copper Thickness: 1oz/2oz/3oz(35μm/70μm/105μm)
Here is the link for you to check.
https://www.pcbway.com/capabilities.html
The property of a dielectric which determines the electrostatic energy stored per unite volume for a potential gradient
Here is a link for you to refer about the Dielectric constant..
https://en.wikipedia.org/wiki/Relative_permittivity
What are the thicknesses of the Dielectric and copper? What is the Dielectric constant? For a two layer 1.6mm board.